This invention relates to new reaction products based on tertiary amines which may be used as catalysts in the production of isocyanate-based plastics.
The use of salt catalysts based on tertiary amines and mineral acids or organic mono- and polycarboxylic acids in the production of polyurethane foam is already known.
British Pat. No. 1,083,394 describes catalysts made from tertiary amines and mineral acids (such as hydrochloric acid, hydrogen bromide, sulfuric acid, nitric acid and phosphoric acid) with from 0.015 to 0.80 equivalents of acid being used for each equivalent of amine. U.S. Pat. No. 3,193,515 describes the use of salts of boric acid esterified with glycols or glycerol with triethylene diamine as catalysts.
It is also known to use salt catalysts of tertiary amines and organic sulfonic acids and mono- and polycarboxylic acids (G.B. No. 839,185, G.B. No. 794,051, DE-OS No. 2,357,859 and DE-OS No. 2,812,256). These catalysts produce polyurethane foams generally showing adequate properties, but in many cases inadequate expansion power.
Now, rigid polyurethane foam systems in particular have to meet stringent requirements in regard to flow and expansion. This applies in particular to cases where housings having complicated flow paths (for example, refrigerator housings) or particularly long flow paths (for example, hollow bodies for surfboards) are to be filled with foam. In applications such as these, an increased amount of polyurethane reaction mixture is frequently required in order to adequately fill the housing to be filled with foam and to satisfy the physical property requirements of the rigid foam, such as compressive strength and dimensional stability at low temperatures when known salt catalysts or the corresponding tertiary amines are used.
Although expansion power may be increased by increasing the proportion of blowing agent, such as fluorinated hydrocarbons, this is often attended by the disadvantage of increased formation of troublesome bubbles of blowing agent at the surface of the foam and reduced stability in storage of the polyol formulation containing blowing agent.